textproduct: Rapid City

KEY MESSAGES

- Active through Thursday as a series of disturbances move through the region.

- A few severe thunderstorms again possible Wednesday afternoon and evening, especially over northeast Wyoming, the Black Hills, and southwest South Dakota.

- Very hot this weekend into early next week with record high temperatures possible and dangerous heat.

UPDATE

Issued at 1052 PM MDT Tue Jul 7 2026

Massaged PoPs and QPF this evening through the overnight and Wednesday to better match radar trends and the new 00z suite of CAMs. Ongoing showers and thunderstorms should weaken a bit overnight and trend east, ending/exiting the region by sunrise. A break follows before our next round of convection develops around 1-2pm Wednesday afternoon across northeast Wyoming, the Black Hills, and southwest South Dakota. While a couple storms may spill just east of these areas, this region should see most of the activity and the best chance for a few strong to severe storms. SPC maintains a Marginal Risk (Level 1 of 5) of severe thunderstorms in this corridor. Shear around 35kts and decent instability should support pulsing single cells and transient supercell structures with lightning, wind gusts of 50 to 65 MPH, and dime to golf ball size hail. Storms may tend to cluster a bit in the evening, and largely end by 11 PM. Significant heat along with possible critical fire weather conditions still expected to start Saturday and continue into early next week.

DISCUSSION

(This Afternoon Through Monday) Issued at 1025 AM MDT Tue Jul 7 2026

Impulse filled westerly flow will be in place over the region through Thursday as a frontal boundary remains in place. Near daily chances for thunderstorms can be expected with severe storms possible at times, best chances today. Sfc front stalled across the FA today. The front has settled further south that previous model runs indicated yesterday, with a southward shift of the best severe potential. Moderately strong impulse will kick out of WY/MT in the the afternoon and evening and will drive CI there. Storms may also fire along the Pine Ridge and INVOF of the front if capping can be overcome. Another location for CI will be northern BH if the inhibition is also overcome. Given progged ML CAPE of 1-2.5 KJ/KG, deep bulk layer shear of 35 to 45 knots (highest north of the sfc front), expect supercells to be possible with strong rotating updrafts, capable of producing large hail and damaging winds. Best chances for rotating storms will be along and north of the sfc front. Still a very small window for tornadoes with any storms near the sfc front, which will start shifting SW into SW SD this afternoon. Storms will carry across the region through the evening and overnight, possibly lingering into the morning Wed as elevated activity. More storms are possible Wed and Thur as sufficient LL moisture will be in place with weak stability and additional impulses. The best chances for storms will be across the western third Wed with chances expanding to the entire FA Thur. Upper ridge builds into the region this weekend, with dry and hot conds expected. Impressive temps of 35 to almost 40C at h85 with close to 6000 H5 heights over WY, will offer record to near record highs well into the 100s with 110 to 115 possible on portions of the Plains, esp Sunday and Monday. Ridge begins to breaks down across the Northern Plains the middle of next week, with storm chances returning as the active northern periphery of the ridge settles south.

AVIATION

(For the 06Z TAFS Through 06Z Wednesday Night) Issued At 1032 PM MDT Tue Jul 7 2026

Thunderstorms will continue move across western South Dakota over the next couple of hours. Frequent lightning and gusty/erratic winds can be expected with any stronger convective cores. Transient MVFR/IFR conditions also expected around any heavier precipitation cores. Conditions will begin to improve around 09z as storms diminish and move out of the region. Areas of lower ceilings and patchy fog may develop over northwestern South Dakota between 06z and 17z; MVFR/IFR conditions are possible.

Another round of storms will begin to develop over northeast Wyoming and western South Dakota starting around 08/19z and lasting through the remainder of the forecast period.

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...None.